The QSFP28 LR4 is a hot-pluggable, four-channel, and full-duplex optical transceiver module designed for long-distance transmission up to 10 km in the 100G Ethernet network with a working bandwidth of 1295nm to 1310nm. This guide provides the definitive roadmap for selecting, deploying, and troubleshooting QSFP28 transceivers while bypassing the painful trial-and-error phase. Below, you will find comprehensive module comparisons, realistic market pricing, and precise vendor compatibility protocols to ensure a. QSFP28 (Quad Small Form-Factor Pluggable 28) enables 100G transmission by aggregating four parallel 25G electrical lanes, delivering an optimal balance of bandwidth efficiency, power consumption, and deployment flexibility. Compared with legacy 40G QSFP+ modules, QSFP28 provides 2. By providing four lanes of 25G, QSFP28 enables a streamlined upgrade path from lower-speed networks, making it a popular choice for scaling data center interconnect (DCI) and. Cisco ® QSFP28 100G ZR extends 100GbE coherent links from QSFP28 ports reaching up to 80km over dark fiber and up to 300km over amplified Dense Wave Division Multiplexing (DWDM) links. With up to 100 Gbps speeds, it is frequently used within data centers, enterprise networks, and telecommunications.